Shimano
Dura-Ace CS-7900 Cassette

Out of Stock

Description

The Shimano Dura-Ace CS-7900 cassette provides you with a wealth of gearing options unlike any previous generation of Dura-Ace. You get an unprecedented 8 different ratios to choose from -- 11-21, 11-23, 11-25, 11-27, 11-28, 12-23, 12-25, and 12-27. The low 6 cogs are steel, and the high 4 cogs are made from titanium. Compared to the CS-7800 cassette, you get a weight savings of 10g (e.g. the 11-23 weighs 166g).

The backbone of the Dura-Ace CS-7900 cassette is its new aluminum carrier unit. Not only is it lighter than the CS-7800's, but it offers a measurable increase in rigidity for improved power transfer when you're putting the hammer down. In addition, Shimano did some re-engineering to the cog teeth profiles. They're fine-tuned to mate to the Dura-Ace CN-7900 chain -- giving you superior shifting on both up-shifts and down-shifts. You'll also experience added drivetrain efficiency since the inner plates of the CN-7900 precisely fit the cog teeth of the CS-7900 cassette. Lighter, stiffer, crisper -- you get improvements all around.

The Shimano Dura-Ace CS-7900 Cassette is compatible with the Dura-Ace RD-7900 rear derailleur and the RD-7800 rear derailleur except for 11-27 and 11-28 . The RD-7800 rear derailleur does not have ample chain wrap capacity to handle the CS-7900 in 11-27 and 11-28. These cassettes must be used with the RD-7900. The CS-7900 is optimized for the Dura-Ace CN-7900 chain, but it is compatible with the Dura-Ace CN-7801 chain.

Two brand-new ratios for Shimano with the Dura-Ace CS-7900 cassette are 11-25 and 11-28.

Here's what others have to say...

View

What is the difference in the ratios for...

What is the difference in the ratios for the dura ace speed cassettes? What is the difference between the 11-25 vs 12-28? How do you know which one is right for you? I live in Florida which is primarily flat with some small hills and I compete in triathlons. I have purchased a set of Profile Design Altair 80 wheels and I want to put on a new cassette. All my components on my Scott Plasma 10 TT bike are Dura ace and I need a recommendation for the cassette.

Have an answer for Kmorrison2255?

11-27 is a good range

Familiarity:
I've put it through the wringer

I have the 11-27 on my bike and it gives me a pretty good range for climbing using a compact crank. It is also amazing how light the cassette is. I have about 4000 km on it and it still looks good and is holding up well.

Have an answer for sar4885731?

I am getting ready to ride a very hilly...

I am getting ready to ride a very hilly century ride in northern Georgia called "the Six Gap". It has 11,000 feet of climb, just climbing over the six gaps, and doesn't count the mountains in between, which I am told adds another 6,000 feet of climbing. I am riding a Sram Red compact, Dura Ace derailers(no spellcheck), and a Sram 12/28 cassette. Can I use a larger cassette like 12/30 with the components I have

yes, you shouldn't have a problem with going up to 30 tooth in the rear cassette with a Dura-Ace RD. With a compact crank you will have to be heading up some serious slope to really need it, unless you ride with Contador-style cadence on the climbs.

Have an answer for tookor?

Really smooth cassette

I've been training and racing with the CS-7900 for two race seasons. I push all my equipment to the limit, and I did the same with this cassette. It's always smooth and precise, regardless the conditions or wear.

Comment on cesar grajales's review:

The best!

Great cassettes, the best you can buy. I think I've used a ten speed dura ace 11-23 cassette for 5 years on and off for training. Keep it clean and it will last for a long time, and still be lighter than what you had before.

You may not have to use it but it doesn't hurt. I've been fine with using the just the Mavic spacer and no Shimano spacer on some Mavic wheels. Bottom line, if you install everything and get the lock-ring tightened up and the cogs don't have any side to side play, then you're good!

Does anyone know if the 11-27 and 11-28...

The best answer you will get on this is "Probably" and until you see it don't believe it.

In reality they are several technical changes to the 7900 series so if you are running SRAM Red why wouldn't you just get the OG-1090 cassette in 11/28 size? It is just as light, lasts for more miles, and is cheaper than the CS-7900 cassette.

Have an answer for bengipson1614526?

Hi,I'm building a 10-speed road bike for...

Hi,I'm building a 10-speed road bike for ALC8.And so far I've purchased the Ultegra Double Crank and Ultegra Shifters from you guys. Will this cassette be compatible? And What other parts should I get? Thanks in advance!

Yes this cassette is compatible, but it seems pricy for the mix of parts you are starting with. AN Ultegra would save you lots of $$.....which you could spend on lots of extra cleats for your pedals, or at least some cleat covers! As a 2 time mechanic for the ALC I've seen rides ruined by a lack of cleats. A couple spare tubes would be cool too.